A Review of United States Air Force and Department of Defense Aerospace Propulsion Needs (2006) / Chapter Skim
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5 Rocket Propulsion Systems for In-space Operations and Missiles
5 Rocket Propulsion Systems for In-space Operations and Missiles
Pages 171-202
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From page 171... ...
As indicated in Figure 5-1, the Air Force will continue to identify needs for responsive and rapid introduction or repositioning of military satellites or space vehicles of various types for surveillance, defensive or offensive deployment, access to local theater military operations, and, secondarily, for situational awareness. There are a number of approaches to meeting these various military needs.
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From page 172... ...
172 A REVIEW OF AEROSPACE PROPULSION NEEDS Theater Buildup Theater Operations Weeks - Months Months Strategic and Responsive Space ytivticA Capital Assets UAVs and Air Assets Use/ Low Tempo High Tempo Ops Ops If Space Assets Attacked Time · Intelligence Initial Battle Early Ground Stabilization Gathering Indications Preparations Conflict War & Peace · Training of Conflict Control of Keeping · Contingency Air Space Operations FIGURE 5-1 Responsive space utility. SOURCE: James (2005)
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From page 173... ...
Monopropellants Monopropellant hydrazine thrusters have typical performance characteristics as follows: · Thrust range: 0.025-125 lbf · Isp range: 225-239 lbf-sec/lbm · Restart capability: 750,000 starts at 50 lbf · Pressure operating range: 350 psia blowdown at 100 psia · Radiative thermal control There are three manufacturers of catalytically decomposed monopropellant hydrazine engines in the United States: Aerojet, in Redmond, Washington; American Pacific, in Niagara Falls, New York; and Northrop Grumman Space Division, in Redondo Beach, California. Bipropellants The bipropellant chemical propulsion system MON/MMH has typical performance characteristics as follows: · Thrust range: 0.4-5 lbf · Isp range: 250-295 lbf-sec/lbm · Restart capability: multiple · Pressure operating range: 350 psia blowdown at 100 psia · Radiative thermal control In this same thrust class, an innovative bipropellant thruster, secondary combustion augmented thruster (SCAT)
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From page 174... ...
174 A REVIEW OF AEROSPACE PROPULSION NEEDS · Thrust range: 100-110 lbf · Isp range: 305-326 lbf-sec/lbm · Restart capability: multiple · Engine inlet operating pressure: 250 psia · Radiative/film thermal control MON/MMH liquid apogee engines are typically used in combination with the low-thrust MON/MMH thrusters used for on-orbit propulsive functions. MON/N2H4 liquid apogee engines are advantageous for spacecraft propulsion systems that use monopropellant hydrazine or electrothermal hydrazine or hydrazine arcjet thrusters for on-orbit propulsive functions.
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ROCKET PROPULSION SYSTEMS FOR IN-SPACE OPERATIONS AND MISSILES 175 FIGURE 5-2 Operational satellites with electric propulsion. SOURCE: Aerojet (2006)
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176 A REVIEW OF AEROSPACE PROPULSION NEEDS FIGURE 5-3 Aerojet MR-501B electrothermal hydrazine thruster (EHT)
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ROCKET PROPULSION SYSTEMS FOR IN-SPACE OPERATIONS AND MISSILES 177 FIGURE 5-4 MR-510 arcjet thruster and cable assembly. SOURCE: Aerojet (2004b)
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178 A REVIEW OF AEROSPACE PROPULSION NEEDS mode produces 165 mN thrust at an Isp of about 3,500 seconds. The high-power mode is used exclusively for the orbit insertion phase, which greatly reduces the amount of chemical propellant carried by the spacecraft for this task.
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. Aerojet Redmond has completed flight qualification of the BPT-4000, shown in Figure 5-6, for the Lockheed Martin build of the Air Force advanced EHF satellites.
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180 A REVIEW OF AEROSPACE PROPULSION NEEDS well suited to missions with high V requirements. In addition to satellite NSSK and partial orbit transfer requirements, Hall thrusters would be suitable for applications such as Earth transfer missions.
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ROCKET PROPULSION SYSTEMS FOR IN-SPACE OPERATIONS AND MISSILES 181 constraints that come from the satellite's small size. The most promising technologies under investigation to date for near- and intermediate-term military applications appear to be micronewton PPTs, colloid thrusters and ion thrusters, and both ion grid thrusters and Hall effect thrusters.
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From page 182... ...
PROMISING TECHNOLOGIES FOR ON-ORBIT PROPULSION AND FOR TACTICAL AND STRIKE MISSILES IHPRPT Targets for Propulsion Performance The Integrated High-Payoff Rocket Propulsion Technology (IHPRPT) program of DoD, the Air Force, and NASA is a joint government and industry effort focused on developing technologies for military global reach, strategic missiles, long life or spacecraft capability, and tactical missiles.
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ROCKET PROPULSION SYSTEMS FOR IN-SPACE OPERATIONS AND MISSILES 183 maneuvering, and attitude control. Objectives of the R&D are given in Table 5-6.
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The present plan is to demonstrate the transfer of hydrazine only. The subsequent transition to a fully operational hydrazine transfer docking satellite and autonomous servicing system could have important benefits for assembly command ship and orbit adjustments of future Air Force satellite constellations.
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From page 185... ...
that a real payoff can be achieved by electric propulsion on orbit. Under IHRPRT, the Air Force has grouped new concepts for in-space electric propulsion systems into four types: · Type A, orbit insertion and circularization -- 4.5-kW Hall-effect thruster -- 25 cm gridded xenon ion thruster -- 20-kW Hall-effect thruster -- XOCOT (type of pulsed plasma thruster)
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From page 186... ...
All the warfighting Services (the Army, the Air Force, the Navy, and the Marine Corps) rely heavily on various types of rocket-propelled missiles for both defensive and offensive purposes.
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program for electric propulsion called for in Recommendation 5-1. The prioritization and scheduling of work to address these needs within the overall S&T budget could come out of an objective review of Air Force in-space mission plans.
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L-3 Communications Electron Technologies, Inc., and Aerojet Redmond are sources for gridded ion thrusters. 2For additional information on the successful June 2006 flight of the 200-W Hall thruster, see the Air Force Research Laboratory web site at http://afrlhorizons.com/0001/t.html#Aug06.
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From page 189... ...
Basic, essentially research-level work in a number of very advanced areas seems to be of high quality. However, the committee does not have enough information about the actual future requirements for DoD and Air Force airborne missiles, particularly for responsive near-space operations, to allow it to objectively prioritize these projects.
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190 A REVIEW OF AEROSPACE PROPULSION NEEDS intent is to replace empirical models with more physics-based models. The goals of the programs are to conduct trade studies at the system, subsystem component, and material levels to refine technology selection and evaluation, to develop and validate the advanced computational tools needed to support design/analysis of advanced concepts, to identify and correct deficiencies in material property information needed to support program objectives, to perform initial validation of motor component materials and design suitability to meet Phase III goals through Battlefield Artillery Tactical Engagement System (BATES)
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Elkton's tactical products include small tactical motors and gas generators for the Navy that are used in vertical launch antisubmarine rockets and Harpoon missiles.
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192 A REVIEW OF AEROSPACE PROPULSION NEEDS · Storable liquid propellant systems provide total thrust flexibility at high combustion efficiency. Liquid propellants for tactical missiles have not found favor with any of the Services and will not be discussed further in this report.
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ROCKET PROPULSION SYSTEMS FOR IN-SPACE OPERATIONS AND MISSILES 193 FIGURE 5-9 Hybrid missile concepts. SOURCE: Morrison (2005)
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194 A REVIEW OF AEROSPACE PROPULSION NEEDS FIGURE 5-10 Hybrid motor performance at different expansion ratios. SOURCE: Lockheed Martin Space Systems Company.
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ROCKET PROPULSION SYSTEMS FOR IN-SPACE OPERATIONS AND MISSILES 195 the staged combustion system and showed significantly higher performance and stability within 2.5 percent of the average chamber pressure (typical solid propulsion stability is 5 percent of the average chamber pressure)
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196 A REVIEW OF AEROSPACE PROPULSION NEEDS containing the combustion products of hybrid motors. Rapid nozzle throat erosion does not affect the hybrid fuel burn rate, but it does reduce the nozzle expansion ratio and chamber pressure as a function of time, which eventually degrades performance.
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From page 197... ...
satisfies four key requirements: effective energy/trajectory management; higher-energy-density performance; minimum smoke exhaust; and insensitive propellants. The S&T part of the DoD/Air Force strategic plan for missiles should focus on the technologies and design criteria necessary to meet these goals.
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From page 198... ...
Two concepts for space access launch vehicles were described and discussed in Chapter 4. The BAE Systems concept utilizes self-contained air-based vertical launch (ABVL)
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Recommendation 5-5. The Air Force should sponsor basic missile/environment dynamics measurements and detailed system engineering studies to fully understand the transformational potential of utilizing airbased vertical launch concepts for various types and sizes of prompt-response military missiles.
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From page 200... ...
The Air Force and DoD should sponsor a detailed system engineering study of using the Multi-Mission Modular Vehicle air-based launch system for medium-sized vehicles could be combined in combination with a study on using air-based vertical launch for small vehicles, ensuring they are focused on Air Force/DoD mission success optimization criteria. The studies would identify the propulsion technologies (modifications or new concepts)
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From page 201... ...
Unless a serious commitment to reversing this trend is made, the ability of the industry to provide the high-quality engineering and production capability necessary to realize the Air Force's medium- and far-term goals for access to space, in-space operations, and missiles must be considered at risk. REFERENCES Published Benson, S
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From page 202... ...
July. Mike Huggins, Air Force Research Laboratory.
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